Portable crane



Patented Aug. 14, 1945 A UNITED Y I-SYTATES PATENT OFFICE YLadALIHei-cik, Lakewood, Ohio, assignor a The Hill Acme Company,Cleveland, Ohio, a cor-- poration of Ohio Application January 26, 1944;Serial No. 51.9,711

4 Claims.

This invention relates to portable cranes and particularly to that typeof portable crane which is used in shops or warehouses for raising andlowering relatively heavy parts and for moving such-parts from one placeto another on the floor. Such cranes are vcry'extensively used inmachine shops for raising parts to be machined from the floor, conveyingthem to machine tools, lifting them into machine tools for machining,and lifting them out of the tools after machining.

For the purpose of moving from place to place, cranes of this type areusually provided with three wheel units which permit the crane, withitssuspended load, to'be rolled over the floor of the shop. Floors of shopsare usually not level, having high spots and hollows, which frequentlycause the top of the crane standard to tilt laterally to such an extentthat'the crane overturns unless extreme caution is exercised. Theswinging of the suspended weight at a high elevation increases thisdanger of overturning, especially when the operator makes a sharp turnin rolling the crane over the floor. 'Ihe operator also frequently findsit necessary to pull sideways on the suspended load, when loading orunloading the crane, with the result that thecrane tips laterally to adangerous degree and frequently overturns, causing personal injury andseriousdamage to the load and equipment.

It is to benoted that the tendency to overturn is counter-balancedpractically only bythe weight Ill) of one half of the base; and in acrane, which must necessarily be light in weight for the sake ofmobility, this counterbalancing efiect is negligible, and the danger ofoverturning is serious, once the resultant load force falls outside ofthe triangular area defined by the three spaced Wheel units.

The present invention is primarily directed to the preventionof, thisinadvertent overturning, in a crane of the type referred to above.

'It is accordingly the prime object of this invention to provide meansfor preventing the-inadvertent overturning of arollablc floor. crane.either during loading, or rolling on the floor, or unload- It is afurther objectof this invention to provide a crane of this type in whichtilting, to a dangerous degree is prevented by auxiliary devices whichfunction only when the crane tilts to a position in which it would,overturn, if itwere not for the action of these auxiliary overturn preventing devices.

It is a further object of, this invention to pro vide suchoverturnpreventing devices. which will not interfere with the normal operationor action of the crane under any circumstances either in loading,unloading or rolling along the floor and which will act as auxiliaryrollers, in the event that the crane assumes a dangerous tilt outcfplumb when the crane is rolling along the floor.

A further understanding of the construction and operation and of themanner in which the novel features of this invention effect the aboveand further objects will become apparent from the following detaildescription and the annexed drawings, which set forth certain meansembodying this invention, such disclosed means constituti-ng, however,but one of the forms in which the principle of this invention may beapplied.

Referring to theanncxed-drawings:

Fig. 1 is: a side-elevation of a portable crane embodying thisinvention.

Fig. 21s a rear elevation of the crane illustrated in Fig. '1, a certainhandle for maneuverin the crane being shownbroken awayat theaxle.

Fig. 3 isa plan sectional viewof the'crane illustrated inliigures 1 and2, this view being taken frorirthe plane indlcated by line 3'-3', inFigures 1 and'2. v i

This improved portable {crane consists of a base frame indicatedgenerally at I ,an upright standard mounted on the base frame indicatedat I hoisting or lifting mechanism associated with the standardindicatedat 3, and rolling: means ind iarms. 5 is. preferably open andthese arms-are spaced apart a distance sufiiciently wide' to accommodatethe largest piecewhich is intended to be regularly handled. by thecrane. As will appear from Fig. 3 the arms 5 are preferably of bentconformation, the front portions 1' oi the armsbfillflg. substantiallyparallel to the fore and aft: axis A-Xofthe crane (Fig.v 3-) andtherearwardportions 8 of the arms 5 converging toward the rearconnectingv bed or seat .6, the portions 1 and fl each forming. an apexor: elbow'at 9;, where they meet. v

The upright standard 2 is mounted uponuand preferably fi-xed'to the rearconnecting bed or seat :5 of the base frames This standard comprises asubstantially vertical column portion Hi and a forwardly curved. portionI12 terminating at a point substantially vertically above the spacebetween the front ends ofthe arms 5. Thisstandardisformed, for thesake0f lightness, Ofl four tubular members secured-together by zigzag rodlacing in order to combine-lightness and requisite strength. The basel3-of the column i-srpreterably connected to the rear-bed t byrwelding.'Ilhi's shaft H which is in turn supported in a pair of bearing bracketsI8, l8 Fixed to or integrally formed with the drum I6 is a worm gear 19engaged by a worm 20 mounted on a shaft 2| which is rotatably mounted ina pair of bearings 22,

the shaft 20 being formed with a squared end adapted to receive asocketed crank handle 23. The axis of the drum preferably extends in afore and aft direction and the axis of the worm extends in a transversedirection which arrangement aifords ready access to the crank handlefrom the side of the-crane. The drum is preferably located entirelywithin the confines of the vertical column portion H of the uprightstand-, ard 2, as will readily appear from an inspection of Figures 1and 2.

Fixed to the drum. l 6, preferably at its smaller end, is a cable 24.This cable is wound about the surface of the drum and at its free endextends upwardly over a pair of intermediate sheaves 25 and 26 and aterminal sheave 21, these sheaves being rotatably mounted on pins fixedin the curved portion I2 of the standard 2. From the sheave 21 the cable24 loops downwardly and passes around a sheave 28 which supports a worklifting hook 29. The free end of the cable 24 passes upwardly from thesheave 28 to complete the loop and is preferably provided at its endwith a hook 30 which, in the arrangement illustrated in Fig. 1,removably engages an eye 3|, whichis fixed to the forward end of thecurved portion [2 of the standard 2.

When the loads to be lifted are relatively light and a faster speed oflift is possible the hook 30 may be removed from the eye 3| and hookedover the adjacent loop of the cable 24 at a point just above the sheave28, as shown in dot and dash lines in Fig. 1.

It will be understood that a chain, rope or any 2 other equivalent maybe substituted for the cable 24. It will also be clear that a hand wheelor any other device may be used instead of the crank 23. It will also beevident that, altho the hoisting mechanism in the present embodiment ismanually actuated, power driven mechanism may be substituted.

The rolling means 4 consist of a plurality of wheel units which supportthe base frame as follows: At the front the base frame is supported ontwo spaced wheel units each of which consists, in the presentembodiment, of a single wheel 33 rotatably mounted on a pin 34 fixed independing flanges adjacent the front end of the forward portions 1 ofthe arm 5. The axes of the wheels 33 are located transversely withreference. to the fore and aft axis A-X and the plane of rotation of thewheels 33 is accordingly parallel to the fore and aft axis of the base.The rear of the base frame is supported on a wheel unit consisting of apair of spaced wheels 35, 35

mounted on opposed ends of a curved crank r eccentric axle 36 whosecentral portion is journaled in a depending bearing 31 formed upon thelower end of a vertical king pin 38. This king pin 38 is mounted foroscillation about a vertical axis in a bearing 39 secured, by welding orotherwise, to the extreme rear of the connecting bed 6 andin a positionsubstantially centrally of the base frame. Fixed to the axle 36, is thelower forked end of a handle 40, this handle being illustrated inFigures 1 and 3, in an operating position, that is, in a position whichthe handle occupies when the operator is drawing the crane over thefloor. This handle 40 and the eccentric axle 36 are so positioned withrespect to each other, that, when the handle 40 is raised to asubstantially vertical position, the crank portion of the axle 36 in thebearing 31 of the king pin 38, and hence the rear of the base frame I,are lowered slightly, and when the handle is swung downwardly, the crankportion and the base frame, and hence the entire crane structure, areraised a slight amount. As a result of this position of the eccentricaxle 36, with reference to the bearing 3''! just described, the weightof the crane normally tends to swing the handle 40 to a convenientvertical position.

Formed at the lower face of the frame and in a position vertically abovethe wheels 35, 35, are a pair of blocks 4|. These blocks are shownslightly vertically spaced from the Wheels 35, in the position of theparts illustrated in Figures 1 and 2. When, however, the handle 40 israised to substantially the vertical position, the frame lowerssufficiently so that the blocks engage and rest upon the tops of thewheels 35, thereby serving as a brake acting on the wheels to preventthe rolling of the crane, this being the normal condition when the cranehandle is not swung downwardly by the operator. When the handle 40 isslightly lowered from the vertical position the rear of the base frameis raised sufliciently so that the braking blocks 4| are freed from thewheels .35.

It will appear from the above description that the pair of spaced wheels35, 35 move as a single unit and support the base frame at a pointcoincident with the king pin 38 at the extreme rear of the base frameand on the fore and aft center line of thebase frame.

It will further be evident that these wheels 35, 35 can swivel about theking pin 38 to an angle of 90 or more from the full line position shownin Figures 1 and 3, to the dot and dash line DOsi tion shown in Fig. 3,and that the base frame can therefor readily be rolled in any direction.

Located adjacent each elbow or apex 9 of each arm 5 of the base frame islocated a safety wheel unit indicated in its entirety at 45. This unitis preferably of the caster type comprising a roll or wheel 46 mountedin the forked lower end 47 of a swivel pin 48 rotatably mounted foroscillation about a vertical axis in a vertical bearing 49 fixed in anydesired manner to the arm 5. It is to .be noted that the lower point orbottom of the wheel 46 in the safety wheel unit 45 is spaced slightlyabove a plane tangent to the bottoms of the front wheels 33 and the rearwheels 35, that is, slightly above the floor line, as clearly appears inFig, 1. safety wheel unit 45 above the fioor line is preferably soselected that there is'still slight clearance between the floor and thebottom of wheel unit 45 when the frame is in its lowermost position withits rear end resting on the wheels 35.

An inspection of the plan view, Fig. 3, will disclose that the safetywheels 45 are positioned outwardly of vertical planes AC and AB passingthru the center of the rear wheel unit and. the centers of the two frontwheel units, respectively. It will be evident in fact, that the safetywheels are, further, located outwardly of vertical planes D-B and,ECpassing thru the front'wheels The distance of the bottom of the 33, 33and the centers of the spaced rear wheels 35, 35 On the correspondingsides of the crane, respectively, regardless of the angular position ofthe rear wheels; in other words, the swivelled safety wheel units arepositioned laterally outwardly of the quadrilateral defined by thecenters of the spaced front Wheels 33, 33 and the centers of the pair ofrear wheels 35, 35.

An inspection of Fig. 3 will also disclose the fact that the safetywheel units are spaced apart a distance substantially equal to the spacebetween the front wheels 33, 33 and that the safety Wheels aresubstantially alined with the front wheels.

33, 33 in a fore and aft direction. It will also be evident that thecenter to center distance of the safety wheel unit 45 and the frontwheel 33 on the corresponding side of the crane is very nearly the sameas the center to center distance of the safety wheel units 45 and theking pin 38 of the rear Wheel unit.

It will be evidentthat; in rolling on the floor, this crane normallytravels on the two front wheel units 33 and rear wheel unit 35. If,however, one of the front wheel units should strike a high spot orprojection on the fioor, that front wheel and that side of the framewould be lifted in proportion to the height of the projection. Such aninterference on the floor would tend to cause the suspended weight toswing sideways and, if the height of the projection or intensity ofimpact is sufficient, the crane would normally overturn. In the presentconstruction, however, the safety wheel unit engages the floor afteronly a ve y slight tilting of the base frame and this safety wheeltherefor automatically prevents any excessive tilting of the frame. Itwill be apparent that a crane not provided with the safety wheels wouldtilt about the axis AB or AC, whereas a crane equipped with the safetywheels would tilt either about an axis passing thru one of the safetyWheel units and an adjacent wheel unit 33 or 35, and in either case thestabilizing moment would consist ofthe weight of the entire cranestructure and its load.

In the event that one of the front wheels should roll into a depressionon the floor the safety wheels would engage the floor after only a veryslight drop of the front wheel and the crane would immediately besteadied before a tilt or list could create a dangerous overturningcondition.

It is to be noted that, in view of the caster or swivel type ofconstruction used for the safety wheels, no interruption of the rollingaction will occur when the safety wheel engages the floor, regardless ofthe direction in which the crane is moving, nor will the direction inwhich the crane is moving be affected to any material extent by igieengagement of the safety wheels with the It will also be evident that inloading or unloading the crane, any slight tilting of the cranesideways, due to a side pull of the operator, will be resisted by thesafety wheels, and that this action of the safety wheels will occurafter only a very slight tilting of the crane, and as a result,inadvertent dangerous tilting of this. improved crane is eliminated.

Many modifications of this invention and its application will naturallyoccur to those skilled in this art and the present disclosure shouldtherefor be considered as typical only, and I desire not to be limitedto the exact constructions shown and described.

What I claim is: 1. In a portable crane in combination, a generally U-shaped base frame having forwardly projecting arms and a rearconnecting bed, an upright standard supported on the connecting bed,hoisting mechanism associated with the standard for elevating a loadstraddled by the forwardly projecting arms, two laterally spaced wheelunits supporting said arms, a central wheel unit supporting saidconnecting bed, and safety wheel units positioned on the armslaterallyoutwardly of vertical planes intersecting the centers of thefront wheel units and the center of the rear wheel unit, said safetywheel units being approximately equidistant respectively, from saidfront and rear wheel units and the bottoms of the safety wheel unitsbeing positioned slightly above the plane defined by the bottoms of thewheels of the front and rear wheel units.

2. In a portable crane in combination, a base frame, an upright standardsupported on the base frame, hoisting mechanism associated with thestandard, two laterally spaced wheel units supporting the front end ofthe base frame, a central wheel unit supporting the rear end of the baseframe, and safety wheel units positioned laterally outwardly of verticalplanes intersecting the centers of the front wheel units and the centerof the rear wheel unit, said safety wheel units being substantiallyequidistant respectively, from said front and rear wheel units, andbeing substantially alined in a fore and aft direction with the frontwheel units, and the bottoms of the safety wheel units being positionedslightly above the plane defined by the bottoms of the Wheels of thefront and rear wheel units.

3. In a portable crane in combination, a base frame, an upright standardsupported on the base frame, hoisting mechanism associated with thestandard, two laterally spacedwheel units supporting the front endv ofthe base frame, a central rear Wheel unit comprising a vpair of Wheelsmounted on an axle swivelled on a vertical pin intermediate the pair ofwheels supporting the rear end of the base frame, and safety wheel unitsfixed at points on the base frame positioned laterally outwardly ofvertical planes intersecting the centers of the wheels of the frontunits and the centers of the wheels of the rear unit on thecorresponding side of the base frame, when the axle is square with a.fore and aft axis of the base frame, the bottoms of the safety wheelunits being positioned slightly above the plane defined by the bottomsof the wheels of the front and rear wheel units.

4. In a portable crane in combination, a base frame, an upright standardsupported on the base frame, hoisting mechanism associated with thestandard, two laterally spaced wheel units supporting the front end ofthe base frame, a central rear wheel unit comprising a pair of wheels- 7mounted on an axle swivelled on a vertical pin intermediate the pair ofWheels supporting the rear end of the base frame, and swivelled safetywheel units positioned laterally outwardly of the quadrilateral definedby the centers of the spaced wheels of the front units; and the pair ofwheels of the rear unit, the bottoms of the safety wheel units beingpositioned between the front and rear wheel units and slightly above theplane defined by the bottoms of the wheels of the front and rear wheelunits.

LAD L. ruinous.

